66400512 has 72 divisors (see below), whose sum is σ = 182488320. Its totient is φ = 21411840.

The previous prime is 66400493. The next prime is 66400567. The reversal of 66400512 is 21500466.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22414 + ... + 25202.

It is an arithmetic number, because the mean of its divisors is an integer number (2534560).

Almost surely, 2^66400512 is an apocalyptic number.

66400512 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66400512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91244160).

66400512 is an abundant number, since it is smaller than the sum of its proper divisors (116087808).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66400512 is a wasteful number, since it uses less digits than its factorization.

66400512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2839 (or 2825 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 66400512 is about 8148.6509312892. The cubic root of 66400512 is about 404.9398112049.

Adding to 66400512 its reverse (21500466), we get a palindrome (87900978).

The spelling of 66400512 in words is "sixty-six million, four hundred thousand, five hundred twelve".